A 3.3-mile stretch of Firehole Lake Drive — which takes park visitors past Great Fountain Geyser, White Dome Geyser, and Firehole Lake — was shut down Thursday, and remained closed on Monday. The park's social media team published a stunning picture of the road along with a link to their closure announcement on Twitter.

The same heat that drives the geysers was responsible for melting the road, and comes from what scientists call a "caldera," a large lake of molten-hot magma that sits underneath the park. Scientists announced late last year that the caldera is 2.5 times larger than previously thought. In total, its magma chamber is now thought to stretch 55 miles and contain 120-370 cubic miles of molten lava.

Hottle said the melting road wasn't too unusual, and something the park is used to dealing with.

"We see this kind of thing quite a bit," he said.

Al Nash, another Yellowstone spokesman, told The Associated Press that the closure came at a very inconvenient time — the middle of tourist season — but said nonetheless it was paramount that visitors say off the road for their own safety.

"There are plenty of other great places to see thermal features in the park," he said. "I wouldn't risk personal injury to see these during this temporary closure."

In addition to those traveling the park by car, Nash also cautioned hikers, saying they too should steer clear of the affected areas. There's a risk that what looks like solid ground could give way to boiling water, he said.